Enrico Castellani, an Italian artist who was a prominent member of Europe’s postwar avant-garde, died on Dec. 1 at his home in Celleno, Italy, near Rome. He was 87. A spokesman for Lévy Gorvy, the gallery that represents his work in New York and London, said the cause was complications of a respiratory illness.

Mr. Castellani participated in the swirl of movements and self-proclaimed groups, some armed with manifestoes, that flourished on both sides of the Atlantic in the late 1950s and ’60s. They included Group Zero in Germany and the Cobra group in Copenhagen, Brussels and Amsterdam, as well as the circle around Yves Klein in France and the Neo-Concrete artists in Brazil.